Oral and Maxillofacial Pathology
The organizing framework
Classify lesions as developmental, inflammatory, cystic, neoplastic, or systemic, then ask where the lesion is, what it looks like, and what the history contributes.
High-yield entities
- Cysts: the radicular (periapical) cyst is the most common odontogenic cyst and is inflammatory; the dentigerous cyst is the most common developmental odontogenic cyst; the odontogenic keratocyst has a high recurrence rate and a PTCH1 association. Also know lateral periodontal cyst, nasopalatine duct cyst, and glandular odontogenic cyst.
- Tumors: ameloblastoma is the most common clinically significant odontogenic tumor and is locally aggressive; odontoma is the most common odontogenic tumor overall and is hamartomatous. Also cementoblastoma and odontogenic myxoma.
- Mucosal disease: leukoplakia is a clinical diagnosis of exclusion with roughly 5% malignant transformation; erythroplakia carries higher risk. Know oral lichen planus, lichenoid reactions, candidiasis, aphthous ulcers, and nicotinic stomatitis.
- Malignancy: squamous cell carcinoma is the most common oral malignancy; tobacco, alcohol, and betel quid are major risks. Floor of mouth, ventrolateral tongue, and soft palate are high-risk sites.
- Reactive lesions: pyogenic granuloma, peripheral giant cell granuloma, fibrous hyperplasia, mucocele of the lower lip, and ranula of the floor of mouth.
- Fibro-osseous lesions: fibrous dysplasia, ossifying fibroma, cemento-osseous dysplasia.
Traps
A white patch is not a diagnosis; leukoplakia remains a clinical label until biopsy. Most oral cancers present as an ulcer or nonhealing lesion, often painless.
Rule of thumb
Any ulcer present longer than two weeks without an obvious cause warrants biopsy or referral.